.scroll_tip {
  z-index: 1000;
  display: flex;
  flex-flow: column nowrap;
  justify-content: center;
  align-items: center;
  position: fixed;
  left: 50%;
  bottom: .3rem;
  font-size: .36rem;
  font-weight: 700;
  letter-spacing: .02rem;
  transform: translateX(-50%);

  .arrow {
    width: 0.16rem;
    height: 0.16rem;
    border-left: 0.04rem solid #fff;
    border-bottom: 0.04rem solid #fff;
    transform: rotateZ(-45deg);
  }

  .arrow:nth-child(2) {
    animation: OP_ScrollTips 2s infinite;
  }

  .arrow:nth-child(3) {
    animation: OP_ScrollTips 2s 0.2s infinite;
  }

  .arrow:nth-child(4) {
    animation: OP_ScrollTips 2s 0.4s infinite;
  }
}

@keyframes OP_ScrollTips {
  0% {
    opacity: 0.4;
  }

  30% {
    opacity: 1;
  }

  70% {
    opacity: 1;
  }

  100% {
    opacity: 0.4;
  }
}